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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
  * All Rights Reserved.
  */
 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_acl.h"
 #include "xfs_quota.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_attr.h"
 #include "xfs_trans.h"
 #include "xfs_trace.h"
 #include "xfs_icache.h"
 #include "xfs_symlink.h"
 #include "xfs_dir2.h"
 #include "xfs_iomap.h"
 #include "xfs_error.h"
 #include "xfs_ioctl.h"
 #include "xfs_xattr.h"
 
 #include <linux/posix_acl.h>
 #include <linux/security.h>
 #include <linux/iversion.h>
 #include <linux/fiemap.h>
 
 /*
  * Directories have different lock order w.r.t. mmap_lock compared to regular
  * files. This is due to readdir potentially triggering page faults on a user
  * buffer inside filldir(), and this happens with the ilock on the directory
  * held. For regular files, the lock order is the other way around - the
  * mmap_lock is taken during the page fault, and then we lock the ilock to do
  * block mapping. Hence we need a different class for the directory ilock so
  * that lockdep can tell them apart.
  */
 static struct lock_class_key xfs_nondir_ilock_class;
 static struct lock_class_key xfs_dir_ilock_class;
 
 static int
 xfs_initxattrs(
     struct inode        *inode,
     const struct xattr  *xattr_array,
     void            *fs_info)
 {
     const struct xattr  *xattr;
     struct xfs_inode    *ip = XFS_I(inode);
     int         error = 0;
 
     for (xattr = xattr_array; xattr->name != NULL; xattr++) {
         struct xfs_da_args  args = {
             .dp     = ip,
             .attr_filter    = XFS_ATTR_SECURE,
             .name       = xattr->name,
             .namelen    = strlen(xattr->name),
             .value      = xattr->value,
             .valuelen   = xattr->value_len,
         };
         error = xfs_attr_change(&args);
         if (error < 0)
             break;
     }
     return error;
 }
 
 /*
  * Hook in SELinux.  This is not quite correct yet, what we really need
  * here (as we do for default ACLs) is a mechanism by which creation of
  * these attrs can be journalled at inode creation time (along with the
  * inode, of course, such that log replay can't cause these to be lost).
  */
 int
 xfs_inode_init_security(
     struct inode    *inode,
     struct inode    *dir,
     const struct qstr *qstr)
 {
     return security_inode_init_security(inode, dir, qstr,
                          &xfs_initxattrs, NULL);
 }
 
 static void
 xfs_dentry_to_name(
     struct xfs_name *namep,
     struct dentry   *dentry)
 {
     namep->name = dentry->d_name.name;
     namep->len = dentry->d_name.len;
     namep->type = XFS_DIR3_FT_UNKNOWN;
 }
 
 static int
 xfs_dentry_mode_to_name(
     struct xfs_name *namep,
     struct dentry   *dentry,
     int     mode)
 {
     namep->name = dentry->d_name.name;
     namep->len = dentry->d_name.len;
     namep->type = xfs_mode_to_ftype(mode);
 
     if (unlikely(namep->type == XFS_DIR3_FT_UNKNOWN))
         return -EFSCORRUPTED;
 
     return 0;
 }
 
 STATIC void
 xfs_cleanup_inode(
     struct inode    *dir,
     struct inode    *inode,
     struct dentry   *dentry)
 {
     struct xfs_name teardown;
 
     /* Oh, the horror.
      * If we can't add the ACL or we fail in
      * xfs_inode_init_security we must back out.
      * ENOSPC can hit here, among other things.
      */
     xfs_dentry_to_name(&teardown, dentry);
 
     xfs_remove(XFS_I(dir), &teardown, XFS_I(inode));
 }
 
 /*
  * Check to see if we are likely to need an extended attribute to be added to
  * the inode we are about to allocate. This allows the attribute fork to be
  * created during the inode allocation, reducing the number of transactions we
  * need to do in this fast path.
  *
  * The security checks are optimistic, but not guaranteed. The two LSMs that
  * require xattrs to be added here (selinux and smack) are also the only two
  * LSMs that add a sb->s_security structure to the superblock. Hence if security
  * is enabled and sb->s_security is set, we have a pretty good idea that we are
  * going to be asked to add a security xattr immediately after allocating the
  * xfs inode and instantiating the VFS inode.
  */
 static inline bool
 xfs_create_need_xattr(
     struct inode    *dir,
     struct posix_acl *default_acl,
     struct posix_acl *acl)
 {
     if (acl)
         return true;
     if (default_acl)
         return true;
 #if IS_ENABLED(CONFIG_SECURITY)
     if (dir->i_sb->s_security)
         return true;
 #endif
     return false;
 }
 
 
 STATIC int
 xfs_generic_create(
     struct user_namespace   *mnt_userns,
     struct inode    *dir,
     struct dentry   *dentry,
     umode_t     mode,
     dev_t       rdev,
     bool        tmpfile)    /* unnamed file */
 {
     struct inode    *inode;
     struct xfs_inode *ip = NULL;
     struct posix_acl *default_acl, *acl;
     struct xfs_name name;
     int     error;
 
     /*
      * Irix uses Missed'em'V split, but doesn't want to see
      * the upper 5 bits of (14bit) major.
      */
     if (S_ISCHR(mode) || S_ISBLK(mode)) {
         if (unlikely(!sysv_valid_dev(rdev) || MAJOR(rdev) & ~0x1ff))
             return -EINVAL;
     } else {
         rdev = 0;
     }
 
     error = posix_acl_create(dir, &mode, &default_acl, &acl);
     if (error)
         return error;
 
     /* Verify mode is valid also for tmpfile case */
     error = xfs_dentry_mode_to_name(&name, dentry, mode);
     if (unlikely(error))
         goto out_free_acl;
 
     if (!tmpfile) {
         error = xfs_create(mnt_userns, XFS_I(dir), &name, mode, rdev,
                 xfs_create_need_xattr(dir, default_acl, acl),
                 &ip);
     } else {
         error = xfs_create_tmpfile(mnt_userns, XFS_I(dir), mode, &ip);
     }
     if (unlikely(error))
         goto out_free_acl;
 
     inode = VFS_I(ip);
 
     error = xfs_inode_init_security(inode, dir, &dentry->d_name);
     if (unlikely(error))
         goto out_cleanup_inode;
 
     if (default_acl) {
         error = __xfs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
         if (error)
             goto out_cleanup_inode;
     }
     if (acl) {
         error = __xfs_set_acl(inode, acl, ACL_TYPE_ACCESS);
         if (error)
             goto out_cleanup_inode;
     }
 
     xfs_setup_iops(ip);
 
     if (tmpfile) {
         /*
          * The VFS requires that any inode fed to d_tmpfile must have
          * nlink == 1 so that it can decrement the nlink in d_tmpfile.
          * However, we created the temp file with nlink == 0 because
          * we're not allowed to put an inode with nlink > 0 on the
          * unlinked list.  Therefore we have to set nlink to 1 so that
          * d_tmpfile can immediately set it back to zero.
          */
         set_nlink(inode, 1);
         d_tmpfile(dentry, inode);
     } else
         d_instantiate(dentry, inode);
 
     xfs_finish_inode_setup(ip);
 
  out_free_acl:
     posix_acl_release(default_acl);
     posix_acl_release(acl);
     return error;
 
  out_cleanup_inode:
     xfs_finish_inode_setup(ip);
     if (!tmpfile)
         xfs_cleanup_inode(dir, inode, dentry);
     xfs_irele(ip);
     goto out_free_acl;
 }
 
 STATIC int
 xfs_vn_mknod(
     struct user_namespace   *mnt_userns,
     struct inode        *dir,
     struct dentry       *dentry,
     umode_t         mode,
     dev_t           rdev)
 {
     return xfs_generic_create(mnt_userns, dir, dentry, mode, rdev, false);
 }
 
 STATIC int
 xfs_vn_create(
     struct user_namespace   *mnt_userns,
     struct inode        *dir,
     struct dentry       *dentry,
     umode_t         mode,
     bool            flags)
 {
     return xfs_generic_create(mnt_userns, dir, dentry, mode, 0, false);
 }
 
 STATIC int
 xfs_vn_mkdir(
     struct user_namespace   *mnt_userns,
     struct inode        *dir,
     struct dentry       *dentry,
     umode_t         mode)
 {
     return xfs_generic_create(mnt_userns, dir, dentry, mode | S_IFDIR, 0,
                   false);
 }
 
 STATIC struct dentry *
 xfs_vn_lookup(
     struct inode    *dir,
     struct dentry   *dentry,
     unsigned int flags)
 {
     struct inode *inode;
     struct xfs_inode *cip;
     struct xfs_name name;
     int     error;
 
     if (dentry->d_name.len >= MAXNAMELEN)
         return ERR_PTR(-ENAMETOOLONG);
 
     xfs_dentry_to_name(&name, dentry);
     error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
     if (likely(!error))
         inode = VFS_I(cip);
     else if (likely(error == -ENOENT))
         inode = NULL;
     else
         inode = ERR_PTR(error);
     return d_splice_alias(inode, dentry);
 }
 
 STATIC struct dentry *
 xfs_vn_ci_lookup(
     struct inode    *dir,
     struct dentry   *dentry,
     unsigned int flags)
 {
     struct xfs_inode *ip;
     struct xfs_name xname;
     struct xfs_name ci_name;
     struct qstr dname;
     int     error;
 
     if (dentry->d_name.len >= MAXNAMELEN)
         return ERR_PTR(-ENAMETOOLONG);
 
     xfs_dentry_to_name(&xname, dentry);
     error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
     if (unlikely(error)) {
         if (unlikely(error != -ENOENT))
             return ERR_PTR(error);
         /*
          * call d_add(dentry, NULL) here when d_drop_negative_children
          * is called in xfs_vn_mknod (ie. allow negative dentries
          * with CI filesystems).
          */
         return NULL;
     }
 
     /* if exact match, just splice and exit */
     if (!ci_name.name)
         return d_splice_alias(VFS_I(ip), dentry);
 
     /* else case-insensitive match... */
     dname.name = ci_name.name;
     dname.len = ci_name.len;
     dentry = d_add_ci(dentry, VFS_I(ip), &dname);
     kmem_free(ci_name.name);
     return dentry;
 }
 
 STATIC int
 xfs_vn_link(
     struct dentry   *old_dentry,
     struct inode    *dir,
     struct dentry   *dentry)
 {
     struct inode    *inode = d_inode(old_dentry);
     struct xfs_name name;
     int     error;
 
     error = xfs_dentry_mode_to_name(&name, dentry, inode->i_mode);
     if (unlikely(error))
         return error;
 
     error = xfs_link(XFS_I(dir), XFS_I(inode), &name);
     if (unlikely(error))
         return error;
 
     ihold(inode);
     d_instantiate(dentry, inode);
     return 0;
 }
 
 STATIC int
 xfs_vn_unlink(
     struct inode    *dir,
     struct dentry   *dentry)
 {
     struct xfs_name name;
     int     error;
 
     xfs_dentry_to_name(&name, dentry);
 
     error = xfs_remove(XFS_I(dir), &name, XFS_I(d_inode(dentry)));
     if (error)
         return error;
 
     /*
      * With unlink, the VFS makes the dentry "negative": no inode,
      * but still hashed. This is incompatible with case-insensitive
      * mode, so invalidate (unhash) the dentry in CI-mode.
      */
     if (xfs_has_asciici(XFS_M(dir->i_sb)))
         d_invalidate(dentry);
     return 0;
 }
 
 STATIC int
 xfs_vn_symlink(
     struct user_namespace   *mnt_userns,
     struct inode        *dir,
     struct dentry       *dentry,
     const char      *symname)
 {
     struct inode    *inode;
     struct xfs_inode *cip = NULL;
     struct xfs_name name;
     int     error;
     umode_t     mode;
 
     mode = S_IFLNK |
         (irix_symlink_mode ? 0777 & ~current_umask() : S_IRWXUGO);
     error = xfs_dentry_mode_to_name(&name, dentry, mode);
     if (unlikely(error))
         goto out;
 
     error = xfs_symlink(mnt_userns, XFS_I(dir), &name, symname, mode, &cip);
     if (unlikely(error))
         goto out;
 
     inode = VFS_I(cip);
 
     error = xfs_inode_init_security(inode, dir, &dentry->d_name);
     if (unlikely(error))
         goto out_cleanup_inode;
 
     xfs_setup_iops(cip);
 
     d_instantiate(dentry, inode);
     xfs_finish_inode_setup(cip);
     return 0;
 
  out_cleanup_inode:
     xfs_finish_inode_setup(cip);
     xfs_cleanup_inode(dir, inode, dentry);
     xfs_irele(cip);
  out:
     return error;
 }
 
 STATIC int
 xfs_vn_rename(
     struct user_namespace   *mnt_userns,
     struct inode        *odir,
     struct dentry       *odentry,
     struct inode        *ndir,
     struct dentry       *ndentry,
     unsigned int        flags)
 {
     struct inode    *new_inode = d_inode(ndentry);
     int     omode = 0;
     int     error;
     struct xfs_name oname;
     struct xfs_name nname;
 
     if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
         return -EINVAL;
 
     /* if we are exchanging files, we need to set i_mode of both files */
     if (flags & RENAME_EXCHANGE)
         omode = d_inode(ndentry)->i_mode;
 
     error = xfs_dentry_mode_to_name(&oname, odentry, omode);
     if (omode && unlikely(error))
         return error;
 
     error = xfs_dentry_mode_to_name(&nname, ndentry,
                     d_inode(odentry)->i_mode);
     if (unlikely(error))
         return error;
 
     return xfs_rename(mnt_userns, XFS_I(odir), &oname,
               XFS_I(d_inode(odentry)), XFS_I(ndir), &nname,
               new_inode ? XFS_I(new_inode) : NULL, flags);
 }
 
 /*
  * careful here - this function can get called recursively, so
  * we need to be very careful about how much stack we use.
  * uio is kmalloced for this reason...
  */
 STATIC const char *
 xfs_vn_get_link(
     struct dentry       *dentry,
     struct inode        *inode,
     struct delayed_call *done)
 {
     char            *link;
     int         error = -ENOMEM;
 
     if (!dentry)
         return ERR_PTR(-ECHILD);
 
     link = kmalloc(XFS_SYMLINK_MAXLEN+1, GFP_KERNEL);
     if (!link)
         goto out_err;
 
     error = xfs_readlink(XFS_I(d_inode(dentry)), link);
     if (unlikely(error))
         goto out_kfree;
 
     set_delayed_call(done, kfree_link, link);
     return link;
 
  out_kfree:
     kfree(link);
  out_err:
     return ERR_PTR(error);
 }
 
 static uint32_t
 xfs_stat_blksize(
     struct xfs_inode    *ip)
 {
     struct xfs_mount    *mp = ip->i_mount;
 
     /*
      * If the file blocks are being allocated from a realtime volume, then
      * always return the realtime extent size.
      */
     if (XFS_IS_REALTIME_INODE(ip))
         return XFS_FSB_TO_B(mp, xfs_get_extsz_hint(ip));
 
     /*
      * Allow large block sizes to be reported to userspace programs if the
      * "largeio" mount option is used.
      *
      * If compatibility mode is specified, simply return the basic unit of
      * caching so that we don't get inefficient read/modify/write I/O from
      * user apps. Otherwise....
      *
      * If the underlying volume is a stripe, then return the stripe width in
      * bytes as the recommended I/O size. It is not a stripe and we've set a
      * default buffered I/O size, return that, otherwise return the compat
      * default.
      */
     if (xfs_has_large_iosize(mp)) {
         if (mp->m_swidth)
             return XFS_FSB_TO_B(mp, mp->m_swidth);
         if (xfs_has_allocsize(mp))
             return 1U << mp->m_allocsize_log;
     }
 
     return PAGE_SIZE;
 }
 
 STATIC int
 xfs_vn_getattr(
     struct user_namespace   *mnt_userns,
     const struct path   *path,
     struct kstat        *stat,
     u32         request_mask,
     unsigned int        query_flags)
 {
     struct inode        *inode = d_inode(path->dentry);
     struct xfs_inode    *ip = XFS_I(inode);
     struct xfs_mount    *mp = ip->i_mount;
 
     trace_xfs_getattr(ip);
 
     if (xfs_is_shutdown(mp))
         return -EIO;
 
     stat->size = XFS_ISIZE(ip);
     stat->dev = inode->i_sb->s_dev;
     stat->mode = inode->i_mode;
     stat->nlink = inode->i_nlink;
     stat->uid = i_uid_into_mnt(mnt_userns, inode);
     stat->gid = i_gid_into_mnt(mnt_userns, inode);
     stat->ino = ip->i_ino;
     stat->atime = inode->i_atime;
     stat->mtime = inode->i_mtime;
     stat->ctime = inode->i_ctime;
     stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks);
 
     if (xfs_has_v3inodes(mp)) {
         if (request_mask & STATX_BTIME) {
             stat->result_mask |= STATX_BTIME;
             stat->btime = ip->i_crtime;
         }
     }
 
     /*
      * Note: If you add another clause to set an attribute flag, please
      * update attributes_mask below.
      */
     if (ip->i_diflags & XFS_DIFLAG_IMMUTABLE)
         stat->attributes |= STATX_ATTR_IMMUTABLE;
     if (ip->i_diflags & XFS_DIFLAG_APPEND)
         stat->attributes |= STATX_ATTR_APPEND;
     if (ip->i_diflags & XFS_DIFLAG_NODUMP)
         stat->attributes |= STATX_ATTR_NODUMP;
 
     stat->attributes_mask |= (STATX_ATTR_IMMUTABLE |
                   STATX_ATTR_APPEND |
                   STATX_ATTR_NODUMP);
 
     switch (inode->i_mode & S_IFMT) {
     case S_IFBLK:
     case S_IFCHR:
         stat->blksize = BLKDEV_IOSIZE;
         stat->rdev = inode->i_rdev;
         break;
     default:
         stat->blksize = xfs_stat_blksize(ip);
         stat->rdev = 0;
         break;
     }
 
     return 0;
 }
 
 static int
 xfs_vn_change_ok(
     struct user_namespace   *mnt_userns,
     struct dentry       *dentry,
     struct iattr        *iattr)
 {
     struct xfs_mount    *mp = XFS_I(d_inode(dentry))->i_mount;
 
     if (xfs_is_readonly(mp))
         return -EROFS;
 
     if (xfs_is_shutdown(mp))
         return -EIO;
 
     return setattr_prepare(mnt_userns, dentry, iattr);
 }
 
 /*
  * Set non-size attributes of an inode.
  *
  * Caution: The caller of this function is responsible for calling
  * setattr_prepare() or otherwise verifying the change is fine.
  */
 static int
 xfs_setattr_nonsize(
     struct user_namespace   *mnt_userns,
     struct xfs_inode    *ip,
     struct iattr        *iattr)
 {
     xfs_mount_t     *mp = ip->i_mount;
     struct inode        *inode = VFS_I(ip);
     int         mask = iattr->ia_valid;
     xfs_trans_t     *tp;
     int         error;
     kuid_t          uid = GLOBAL_ROOT_UID;
     kgid_t          gid = GLOBAL_ROOT_GID;
     struct xfs_dquot    *udqp = NULL, *gdqp = NULL;
     struct xfs_dquot    *old_udqp = NULL, *old_gdqp = NULL;
 
     ASSERT((mask & ATTR_SIZE) == 0);
 
     /*
      * If disk quotas is on, we make sure that the dquots do exist on disk,
      * before we start any other transactions. Trying to do this later
      * is messy. We don't care to take a readlock to look at the ids
      * in inode here, because we can't hold it across the trans_reserve.
      * If the IDs do change before we take the ilock, we're covered
      * because the i_*dquot fields will get updated anyway.
      */
     if (XFS_IS_QUOTA_ON(mp) && (mask & (ATTR_UID|ATTR_GID))) {
         uint    qflags = 0;
 
         if ((mask & ATTR_UID) && XFS_IS_UQUOTA_ON(mp)) {
             uid = from_vfsuid(mnt_userns, i_user_ns(inode),
                       iattr->ia_vfsuid);
             qflags |= XFS_QMOPT_UQUOTA;
         } else {
             uid = inode->i_uid;
         }
         if ((mask & ATTR_GID) && XFS_IS_GQUOTA_ON(mp)) {
             gid = from_vfsgid(mnt_userns, i_user_ns(inode),
                       iattr->ia_vfsgid);
             qflags |= XFS_QMOPT_GQUOTA;
         }  else {
             gid = inode->i_gid;
         }
 
         /*
          * We take a reference when we initialize udqp and gdqp,
          * so it is important that we never blindly double trip on
          * the same variable. See xfs_create() for an example.
          */
         ASSERT(udqp == NULL);
         ASSERT(gdqp == NULL);
         error = xfs_qm_vop_dqalloc(ip, uid, gid, ip->i_projid,
                        qflags, &udqp, &gdqp, NULL);
         if (error)
             return error;
     }
 
     error = xfs_trans_alloc_ichange(ip, udqp, gdqp, NULL,
             has_capability_noaudit(current, CAP_FOWNER), &tp);
     if (error)
         goto out_dqrele;
 
     /*
      * Register quota modifications in the transaction.  Must be the owner
      * or privileged.  These IDs could have changed since we last looked at
      * them.  But, we're assured that if the ownership did change while we
      * didn't have the inode locked, inode's dquot(s) would have changed
      * also.
      */
     if (XFS_IS_UQUOTA_ON(mp) &&
         i_uid_needs_update(mnt_userns, iattr, inode)) {
         ASSERT(udqp);
         old_udqp = xfs_qm_vop_chown(tp, ip, &ip->i_udquot, udqp);
     }
     if (XFS_IS_GQUOTA_ON(mp) &&
         i_gid_needs_update(mnt_userns, iattr, inode)) {
         ASSERT(xfs_has_pquotino(mp) || !XFS_IS_PQUOTA_ON(mp));
         ASSERT(gdqp);
         old_gdqp = xfs_qm_vop_chown(tp, ip, &ip->i_gdquot, gdqp);
     }
 
     setattr_copy(mnt_userns, inode, iattr);
     xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
     XFS_STATS_INC(mp, xs_ig_attrchg);
 
     if (xfs_has_wsync(mp))
         xfs_trans_set_sync(tp);
     error = xfs_trans_commit(tp);
 
     /*
      * Release any dquot(s) the inode had kept before chown.
      */
     xfs_qm_dqrele(old_udqp);
     xfs_qm_dqrele(old_gdqp);
     xfs_qm_dqrele(udqp);
     xfs_qm_dqrele(gdqp);
 
     if (error)
         return error;
 
     /*
      * XXX(hch): Updating the ACL entries is not atomic vs the i_mode
      *       update.  We could avoid this with linked transactions
      *       and passing down the transaction pointer all the way
      *       to attr_set.  No previous user of the generic
      *       Posix ACL code seems to care about this issue either.
      */
     if (mask & ATTR_MODE) {
         error = posix_acl_chmod(mnt_userns, inode, inode->i_mode);
         if (error)
             return error;
     }
 
     return 0;
 
 out_dqrele:
     xfs_qm_dqrele(udqp);
     xfs_qm_dqrele(gdqp);
     return error;
 }
 
 /*
  * Truncate file.  Must have write permission and not be a directory.
  *
  * Caution: The caller of this function is responsible for calling
  * setattr_prepare() or otherwise verifying the change is fine.
  */
 STATIC int
 xfs_setattr_size(
     struct user_namespace   *mnt_userns,
     struct xfs_inode    *ip,
     struct iattr        *iattr)
 {
     struct xfs_mount    *mp = ip->i_mount;
     struct inode        *inode = VFS_I(ip);
     xfs_off_t       oldsize, newsize;
     struct xfs_trans    *tp;
     int         error;
     uint            lock_flags = 0;
     bool            did_zeroing = false;
 
     ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
     ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
     ASSERT(S_ISREG(inode->i_mode));
     ASSERT((iattr->ia_valid & (ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
         ATTR_MTIME_SET|ATTR_TIMES_SET)) == 0);
 
     oldsize = inode->i_size;
     newsize = iattr->ia_size;
 
     /*
      * Short circuit the truncate case for zero length files.
      */
     if (newsize == 0 && oldsize == 0 && ip->i_df.if_nextents == 0) {
         if (!(iattr->ia_valid & (ATTR_CTIME|ATTR_MTIME)))
             return 0;
 
         /*
          * Use the regular setattr path to update the timestamps.
          */
         iattr->ia_valid &= ~ATTR_SIZE;
         return xfs_setattr_nonsize(mnt_userns, ip, iattr);
     }
 
     /*
      * Make sure that the dquots are attached to the inode.
      */
     error = xfs_qm_dqattach(ip);
     if (error)
         return error;
 
     /*
      * Wait for all direct I/O to complete.
      */
     inode_dio_wait(inode);
 
     /*
      * File data changes must be complete before we start the transaction to
      * modify the inode.  This needs to be done before joining the inode to
      * the transaction because the inode cannot be unlocked once it is a
      * part of the transaction.
      *
      * Start with zeroing any data beyond EOF that we may expose on file
      * extension, or zeroing out the rest of the block on a downward
      * truncate.
      */
     if (newsize > oldsize) {
         trace_xfs_zero_eof(ip, oldsize, newsize - oldsize);
         error = xfs_zero_range(ip, oldsize, newsize - oldsize,
                 &did_zeroing);
     } else {
         /*
          * iomap won't detect a dirty page over an unwritten block (or a
          * cow block over a hole) and subsequently skips zeroing the
          * newly post-EOF portion of the page. Flush the new EOF to
          * convert the block before the pagecache truncate.
          */
         error = filemap_write_and_wait_range(inode->i_mapping, newsize,
                              newsize);
         if (error)
             return error;
         error = xfs_truncate_page(ip, newsize, &did_zeroing);
     }
 
     if (error)
         return error;
 
     /*
      * We've already locked out new page faults, so now we can safely remove
      * pages from the page cache knowing they won't get refaulted until we
      * drop the XFS_MMAP_EXCL lock after the extent manipulations are
      * complete. The truncate_setsize() call also cleans partial EOF page
      * PTEs on extending truncates and hence ensures sub-page block size
      * filesystems are correctly handled, too.
      *
      * We have to do all the page cache truncate work outside the
      * transaction context as the "lock" order is page lock->log space
      * reservation as defined by extent allocation in the writeback path.
      * Hence a truncate can fail with ENOMEM from xfs_trans_alloc(), but
      * having already truncated the in-memory version of the file (i.e. made
      * user visible changes). There's not much we can do about this, except
      * to hope that the caller sees ENOMEM and retries the truncate
      * operation.
      *
      * And we update in-core i_size and truncate page cache beyond newsize
      * before writeback the [i_disk_size, newsize] range, so we're
      * guaranteed not to write stale data past the new EOF on truncate down.
      */
     truncate_setsize(inode, newsize);
 
     /*
      * We are going to log the inode size change in this transaction so
      * any previous writes that are beyond the on disk EOF and the new
      * EOF that have not been written out need to be written here.  If we
      * do not write the data out, we expose ourselves to the null files
      * problem. Note that this includes any block zeroing we did above;
      * otherwise those blocks may not be zeroed after a crash.
      */
     if (did_zeroing ||
         (newsize > ip->i_disk_size && oldsize != ip->i_disk_size)) {
         error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
                         ip->i_disk_size, newsize - 1);
         if (error)
             return error;
     }
 
     error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
     if (error)
         return error;
 
     lock_flags |= XFS_ILOCK_EXCL;
     xfs_ilock(ip, XFS_ILOCK_EXCL);
     xfs_trans_ijoin(tp, ip, 0);
 
     /*
      * Only change the c/mtime if we are changing the size or we are
      * explicitly asked to change it.  This handles the semantic difference
      * between truncate() and ftruncate() as implemented in the VFS.
      *
      * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
      * special case where we need to update the times despite not having
      * these flags set.  For all other operations the VFS set these flags
      * explicitly if it wants a timestamp update.
      */
     if (newsize != oldsize &&
         !(iattr->ia_valid & (ATTR_CTIME | ATTR_MTIME))) {
         iattr->ia_ctime = iattr->ia_mtime =
             current_time(inode);
         iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME;
     }
 
     /*
      * The first thing we do is set the size to new_size permanently on
      * disk.  This way we don't have to worry about anyone ever being able
      * to look at the data being freed even in the face of a crash.
      * What we're getting around here is the case where we free a block, it
      * is allocated to another file, it is written to, and then we crash.
      * If the new data gets written to the file but the log buffers
      * containing the free and reallocation don't, then we'd end up with
      * garbage in the blocks being freed.  As long as we make the new size
      * permanent before actually freeing any blocks it doesn't matter if
      * they get written to.
      */
     ip->i_disk_size = newsize;
     xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
     if (newsize <= oldsize) {
         error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, newsize);
         if (error)
             goto out_trans_cancel;
 
         /*
          * Truncated "down", so we're removing references to old data
          * here - if we delay flushing for a long time, we expose
          * ourselves unduly to the notorious NULL files problem.  So,
          * we mark this inode and flush it when the file is closed,
          * and do not wait the usual (long) time for writeout.
          */
         xfs_iflags_set(ip, XFS_ITRUNCATED);
 
         /* A truncate down always removes post-EOF blocks. */
         xfs_inode_clear_eofblocks_tag(ip);
     }
 
     ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
     setattr_copy(mnt_userns, inode, iattr);
     xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
     XFS_STATS_INC(mp, xs_ig_attrchg);
 
     if (xfs_has_wsync(mp))
         xfs_trans_set_sync(tp);
 
     error = xfs_trans_commit(tp);
 out_unlock:
     if (lock_flags)
         xfs_iunlock(ip, lock_flags);
     return error;
 
 out_trans_cancel:
     xfs_trans_cancel(tp);
     goto out_unlock;
 }
 
 int
 xfs_vn_setattr_size(
     struct user_namespace   *mnt_userns,
     struct dentry       *dentry,
     struct iattr        *iattr)
 {
     struct xfs_inode    *ip = XFS_I(d_inode(dentry));
     int error;
 
     trace_xfs_setattr(ip);
 
     error = xfs_vn_change_ok(mnt_userns, dentry, iattr);
     if (error)
         return error;
     return xfs_setattr_size(mnt_userns, ip, iattr);
 }
 
 STATIC int
 xfs_vn_setattr(
     struct user_namespace   *mnt_userns,
     struct dentry       *dentry,
     struct iattr        *iattr)
 {
     struct inode        *inode = d_inode(dentry);
     struct xfs_inode    *ip = XFS_I(inode);
     int         error;
 
     if (iattr->ia_valid & ATTR_SIZE) {
         uint            iolock;
 
         xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
         iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
 
         error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
         if (error) {
             xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
             return error;
         }
 
         error = xfs_vn_setattr_size(mnt_userns, dentry, iattr);
         xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
     } else {
         trace_xfs_setattr(ip);
 
         error = xfs_vn_change_ok(mnt_userns, dentry, iattr);
         if (!error)
             error = xfs_setattr_nonsize(mnt_userns, ip, iattr);
     }
 
     return error;
 }
 
 STATIC int
 xfs_vn_update_time(
     struct inode        *inode,
     struct timespec64   *now,
     int         flags)
 {
     struct xfs_inode    *ip = XFS_I(inode);
     struct xfs_mount    *mp = ip->i_mount;
     int         log_flags = XFS_ILOG_TIMESTAMP;
     struct xfs_trans    *tp;
     int         error;
 
     trace_xfs_update_time(ip);
 
     if (inode->i_sb->s_flags & SB_LAZYTIME) {
         if (!((flags & S_VERSION) &&
               inode_maybe_inc_iversion(inode, false)))
             return generic_update_time(inode, now, flags);
 
         /* Capture the iversion update that just occurred */
         log_flags |= XFS_ILOG_CORE;
     }
 
     error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
     if (error)
         return error;
 
     xfs_ilock(ip, XFS_ILOCK_EXCL);
     if (flags & S_CTIME)
         inode->i_ctime = *now;
     if (flags & S_MTIME)
         inode->i_mtime = *now;
     if (flags & S_ATIME)
         inode->i_atime = *now;
 
     xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
     xfs_trans_log_inode(tp, ip, log_flags);
     return xfs_trans_commit(tp);
 }
 
 STATIC int
 xfs_vn_fiemap(
     struct inode        *inode,
     struct fiemap_extent_info *fieinfo,
     u64         start,
     u64         length)
 {
     int         error;
 
     xfs_ilock(XFS_I(inode), XFS_IOLOCK_SHARED);
     if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
         fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
         error = iomap_fiemap(inode, fieinfo, start, length,
                 &xfs_xattr_iomap_ops);
     } else {
         error = iomap_fiemap(inode, fieinfo, start, length,
                 &xfs_read_iomap_ops);
     }
     xfs_iunlock(XFS_I(inode), XFS_IOLOCK_SHARED);
 
     return error;
 }
 
 STATIC int
 xfs_vn_tmpfile(
     struct user_namespace   *mnt_userns,
     struct inode        *dir,
     struct dentry       *dentry,
     umode_t         mode)
 {
     return xfs_generic_create(mnt_userns, dir, dentry, mode, 0, true);
 }
 
 static const struct inode_operations xfs_inode_operations = {
     .get_acl        = xfs_get_acl,
     .set_acl        = xfs_set_acl,
     .getattr        = xfs_vn_getattr,
     .setattr        = xfs_vn_setattr,
     .listxattr      = xfs_vn_listxattr,
     .fiemap         = xfs_vn_fiemap,
     .update_time        = xfs_vn_update_time,
     .fileattr_get       = xfs_fileattr_get,
     .fileattr_set       = xfs_fileattr_set,
 };
 
 static const struct inode_operations xfs_dir_inode_operations = {
     .create         = xfs_vn_create,
     .lookup         = xfs_vn_lookup,
     .link           = xfs_vn_link,
     .unlink         = xfs_vn_unlink,
     .symlink        = xfs_vn_symlink,
     .mkdir          = xfs_vn_mkdir,
     /*
      * Yes, XFS uses the same method for rmdir and unlink.
      *
      * There are some subtile differences deeper in the code,
      * but we use S_ISDIR to check for those.
      */
     .rmdir          = xfs_vn_unlink,
     .mknod          = xfs_vn_mknod,
     .rename         = xfs_vn_rename,
     .get_acl        = xfs_get_acl,
     .set_acl        = xfs_set_acl,
     .getattr        = xfs_vn_getattr,
     .setattr        = xfs_vn_setattr,
     .listxattr      = xfs_vn_listxattr,
     .update_time        = xfs_vn_update_time,
     .tmpfile        = xfs_vn_tmpfile,
     .fileattr_get       = xfs_fileattr_get,
     .fileattr_set       = xfs_fileattr_set,
 };
 
 static const struct inode_operations xfs_dir_ci_inode_operations = {
     .create         = xfs_vn_create,
     .lookup         = xfs_vn_ci_lookup,
     .link           = xfs_vn_link,
     .unlink         = xfs_vn_unlink,
     .symlink        = xfs_vn_symlink,
     .mkdir          = xfs_vn_mkdir,
     /*
      * Yes, XFS uses the same method for rmdir and unlink.
      *
      * There are some subtile differences deeper in the code,
      * but we use S_ISDIR to check for those.
      */
     .rmdir          = xfs_vn_unlink,
     .mknod          = xfs_vn_mknod,
     .rename         = xfs_vn_rename,
     .get_acl        = xfs_get_acl,
     .set_acl        = xfs_set_acl,
     .getattr        = xfs_vn_getattr,
     .setattr        = xfs_vn_setattr,
     .listxattr      = xfs_vn_listxattr,
     .update_time        = xfs_vn_update_time,
     .tmpfile        = xfs_vn_tmpfile,
     .fileattr_get       = xfs_fileattr_get,
     .fileattr_set       = xfs_fileattr_set,
 };
 
 static const struct inode_operations xfs_symlink_inode_operations = {
     .get_link       = xfs_vn_get_link,
     .getattr        = xfs_vn_getattr,
     .setattr        = xfs_vn_setattr,
     .listxattr      = xfs_vn_listxattr,
     .update_time        = xfs_vn_update_time,
 };
 
 /* Figure out if this file actually supports DAX. */
 static bool
 xfs_inode_supports_dax(
     struct xfs_inode    *ip)
 {
     struct xfs_mount    *mp = ip->i_mount;
 
     /* Only supported on regular files. */
     if (!S_ISREG(VFS_I(ip)->i_mode))
         return false;
 
     /* Only supported on non-reflinked files. */
     if (xfs_is_reflink_inode(ip))
         return false;
 
     /* Block size must match page size */
     if (mp->m_sb.sb_blocksize != PAGE_SIZE)
         return false;
 
     /* Device has to support DAX too. */
     return xfs_inode_buftarg(ip)->bt_daxdev != NULL;
 }
 
 static bool
 xfs_inode_should_enable_dax(
     struct xfs_inode *ip)
 {
     if (!IS_ENABLED(CONFIG_FS_DAX))
         return false;
     if (xfs_has_dax_never(ip->i_mount))
         return false;
     if (!xfs_inode_supports_dax(ip))
         return false;
     if (xfs_has_dax_always(ip->i_mount))
         return true;
     if (ip->i_diflags2 & XFS_DIFLAG2_DAX)
         return true;
     return false;
 }
 
 void
 xfs_diflags_to_iflags(
     struct xfs_inode    *ip,
     bool init)
 {
     struct inode            *inode = VFS_I(ip);
     unsigned int            xflags = xfs_ip2xflags(ip);
     unsigned int            flags = 0;
 
     ASSERT(!(IS_DAX(inode) && init));
 
     if (xflags & FS_XFLAG_IMMUTABLE)
         flags |= S_IMMUTABLE;
     if (xflags & FS_XFLAG_APPEND)
         flags |= S_APPEND;
     if (xflags & FS_XFLAG_SYNC)
         flags |= S_SYNC;
     if (xflags & FS_XFLAG_NOATIME)
         flags |= S_NOATIME;
     if (init && xfs_inode_should_enable_dax(ip))
         flags |= S_DAX;
 
     /*
      * S_DAX can only be set during inode initialization and is never set by
      * the VFS, so we cannot mask off S_DAX in i_flags.
      */
     inode->i_flags &= ~(S_IMMUTABLE | S_APPEND | S_SYNC | S_NOATIME);
     inode->i_flags |= flags;
 }
 
 /*
  * Initialize the Linux inode.
  *
  * When reading existing inodes from disk this is called directly from xfs_iget,
  * when creating a new inode it is called from xfs_init_new_inode after setting
  * up the inode. These callers have different criteria for clearing XFS_INEW, so
  * leave it up to the caller to deal with unlocking the inode appropriately.
  */
 void
 xfs_setup_inode(
     struct xfs_inode    *ip)
 {
     struct inode        *inode = &ip->i_vnode;
     gfp_t           gfp_mask;
 
     inode->i_ino = ip->i_ino;
     inode->i_state |= I_NEW;
 
     inode_sb_list_add(inode);
     /* make the inode look hashed for the writeback code */
     inode_fake_hash(inode);
 
     i_size_write(inode, ip->i_disk_size);
     xfs_diflags_to_iflags(ip, true);
 
     if (S_ISDIR(inode->i_mode)) {
         /*
          * We set the i_rwsem class here to avoid potential races with
          * lockdep_annotate_inode_mutex_key() reinitialising the lock
          * after a filehandle lookup has already found the inode in
          * cache before it has been unlocked via unlock_new_inode().
          */
         lockdep_set_class(&inode->i_rwsem,
                   &inode->i_sb->s_type->i_mutex_dir_key);
         lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class);
     } else {
         lockdep_set_class(&ip->i_lock.mr_lock, &xfs_nondir_ilock_class);
     }
 
     /*
      * Ensure all page cache allocations are done from GFP_NOFS context to
      * prevent direct reclaim recursion back into the filesystem and blowing
      * stacks or deadlocking.
      */
     gfp_mask = mapping_gfp_mask(inode->i_mapping);
     mapping_set_gfp_mask(inode->i_mapping, (gfp_mask & ~(__GFP_FS)));
 
     /*
      * If there is no attribute fork no ACL can exist on this inode,
      * and it can't have any file capabilities attached to it either.
      */
     if (!xfs_inode_has_attr_fork(ip)) {
         inode_has_no_xattr(inode);
         cache_no_acl(inode);
     }
 }
 
 void
 xfs_setup_iops(
     struct xfs_inode    *ip)
 {
     struct inode        *inode = &ip->i_vnode;
 
     switch (inode->i_mode & S_IFMT) {
     case S_IFREG:
         inode->i_op = &xfs_inode_operations;
         inode->i_fop = &xfs_file_operations;
         if (IS_DAX(inode))
             inode->i_mapping->a_ops = &xfs_dax_aops;
         else
             inode->i_mapping->a_ops = &xfs_address_space_operations;
         break;
     case S_IFDIR:
         if (xfs_has_asciici(XFS_M(inode->i_sb)))
             inode->i_op = &xfs_dir_ci_inode_operations;
         else
             inode->i_op = &xfs_dir_inode_operations;
         inode->i_fop = &xfs_dir_file_operations;
         break;
     case S_IFLNK:
         inode->i_op = &xfs_symlink_inode_operations;
         break;
     default:
         inode->i_op = &xfs_inode_operations;
         init_special_inode(inode, inode->i_mode, inode->i_rdev);
         break;
     }
 }

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