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 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (C) 2007 Oracle.  All rights reserved.
  */
 
 #ifndef BTRFS_INODE_H
 #define BTRFS_INODE_H
 
 #include <linux/hash.h>
 #include <linux/refcount.h>
 #include "extent_map.h"
 #include "extent_io.h"
 #include "ordered-data.h"
 #include "delayed-inode.h"
 
 /*
  * Since we search a directory based on f_pos (struct dir_context::pos) we have
  * to start at 2 since '.' and '..' have f_pos of 0 and 1 respectively, so
  * everybody else has to start at 2 (see btrfs_real_readdir() and dir_emit_dots()).
  */
 #define BTRFS_DIR_START_INDEX 2
 
 /*
  * ordered_data_close is set by truncate when a file that used
  * to have good data has been truncated to zero.  When it is set
  * the btrfs file release call will add this inode to the
  * ordered operations list so that we make sure to flush out any
  * new data the application may have written before commit.
  */
 enum {
     BTRFS_INODE_FLUSH_ON_CLOSE,
     BTRFS_INODE_DUMMY,
     BTRFS_INODE_IN_DEFRAG,
     BTRFS_INODE_HAS_ASYNC_EXTENT,
      /*
       * Always set under the VFS' inode lock, otherwise it can cause races
       * during fsync (we start as a fast fsync and then end up in a full
       * fsync racing with ordered extent completion).
       */
     BTRFS_INODE_NEEDS_FULL_SYNC,
     BTRFS_INODE_COPY_EVERYTHING,
     BTRFS_INODE_IN_DELALLOC_LIST,
     BTRFS_INODE_HAS_PROPS,
     BTRFS_INODE_SNAPSHOT_FLUSH,
     /*
      * Set and used when logging an inode and it serves to signal that an
      * inode does not have xattrs, so subsequent fsyncs can avoid searching
      * for xattrs to log. This bit must be cleared whenever a xattr is added
      * to an inode.
      */
     BTRFS_INODE_NO_XATTRS,
     /*
      * Set when we are in a context where we need to start a transaction and
      * have dirty pages with the respective file range locked. This is to
      * ensure that when reserving space for the transaction, if we are low
      * on available space and need to flush delalloc, we will not flush
      * delalloc for this inode, because that could result in a deadlock (on
      * the file range, inode's io_tree).
      */
     BTRFS_INODE_NO_DELALLOC_FLUSH,
     /*
      * Set when we are working on enabling verity for a file. Computing and
      * writing the whole Merkle tree can take a while so we want to prevent
      * races where two separate tasks attempt to simultaneously start verity
      * on the same file.
      */
     BTRFS_INODE_VERITY_IN_PROGRESS,
 };
 
 /* in memory btrfs inode */
 struct btrfs_inode {
     /* which subvolume this inode belongs to */
     struct btrfs_root *root;
 
     /* key used to find this inode on disk.  This is used by the code
      * to read in roots of subvolumes
      */
     struct btrfs_key location;
 
     /*
      * Lock for counters and all fields used to determine if the inode is in
      * the log or not (last_trans, last_sub_trans, last_log_commit,
      * logged_trans), to access/update new_delalloc_bytes and to update the
      * VFS' inode number of bytes used.
      */
     spinlock_t lock;
 
     /* the extent_tree has caches of all the extent mappings to disk */
     struct extent_map_tree extent_tree;
 
     /* the io_tree does range state (DIRTY, LOCKED etc) */
     struct extent_io_tree io_tree;
 
     /* special utility tree used to record which mirrors have already been
      * tried when checksums fail for a given block
      */
     struct extent_io_tree io_failure_tree;
 
     /*
      * Keep track of where the inode has extent items mapped in order to
      * make sure the i_size adjustments are accurate
      */
     struct extent_io_tree file_extent_tree;
 
     /* held while logging the inode in tree-log.c */
     struct mutex log_mutex;
 
     /* used to order data wrt metadata */
     struct btrfs_ordered_inode_tree ordered_tree;
 
     /* list of all the delalloc inodes in the FS.  There are times we need
      * to write all the delalloc pages to disk, and this list is used
      * to walk them all.
      */
     struct list_head delalloc_inodes;
 
     /* node for the red-black tree that links inodes in subvolume root */
     struct rb_node rb_node;
 
     unsigned long runtime_flags;
 
     /* Keep track of who's O_SYNC/fsyncing currently */
     atomic_t sync_writers;
 
     /* full 64 bit generation number, struct vfs_inode doesn't have a big
      * enough field for this.
      */
     u64 generation;
 
     /*
      * transid of the trans_handle that last modified this inode
      */
     u64 last_trans;
 
     /*
      * transid that last logged this inode
      */
     u64 logged_trans;
 
     /*
      * log transid when this inode was last modified
      */
     int last_sub_trans;
 
     /* a local copy of root's last_log_commit */
     int last_log_commit;
 
     /*
      * Total number of bytes pending delalloc, used by stat to calculate the
      * real block usage of the file. This is used only for files.
      */
     u64 delalloc_bytes;
 
     union {
         /*
          * Total number of bytes pending delalloc that fall within a file
          * range that is either a hole or beyond EOF (and no prealloc extent
          * exists in the range). This is always <= delalloc_bytes and this
          * is used only for files.
          */
         u64 new_delalloc_bytes;
         /*
          * The offset of the last dir index key that was logged.
          * This is used only for directories.
          */
         u64 last_dir_index_offset;
     };
 
     /*
      * total number of bytes pending defrag, used by stat to check whether
      * it needs COW.
      */
     u64 defrag_bytes;
 
     /*
      * the size of the file stored in the metadata on disk.  data=ordered
      * means the in-memory i_size might be larger than the size on disk
      * because not all the blocks are written yet.
      */
     u64 disk_i_size;
 
     /*
      * If this is a directory then index_cnt is the counter for the index
      * number for new files that are created. For an empty directory, this
      * must be initialized to BTRFS_DIR_START_INDEX.
      */
     u64 index_cnt;
 
     /* Cache the directory index number to speed the dir/file remove */
     u64 dir_index;
 
     /* the fsync log has some corner cases that mean we have to check
      * directories to see if any unlinks have been done before
      * the directory was logged.  See tree-log.c for all the
      * details
      */
     u64 last_unlink_trans;
 
     /*
      * The id/generation of the last transaction where this inode was
      * either the source or the destination of a clone/dedupe operation.
      * Used when logging an inode to know if there are shared extents that
      * need special care when logging checksum items, to avoid duplicate
      * checksum items in a log (which can lead to a corruption where we end
      * up with missing checksum ranges after log replay).
      * Protected by the vfs inode lock.
      */
     u64 last_reflink_trans;
 
     /*
      * Number of bytes outstanding that are going to need csums.  This is
      * used in ENOSPC accounting.
      */
     u64 csum_bytes;
 
     /* Backwards incompatible flags, lower half of inode_item::flags  */
     u32 flags;
     /* Read-only compatibility flags, upper half of inode_item::flags */
     u32 ro_flags;
 
     /*
      * Counters to keep track of the number of extent item's we may use due
      * to delalloc and such.  outstanding_extents is the number of extent
      * items we think we'll end up using, and reserved_extents is the number
      * of extent items we've reserved metadata for.
      */
     unsigned outstanding_extents;
 
     struct btrfs_block_rsv block_rsv;
 
     /*
      * Cached values of inode properties
      */
     unsigned prop_compress;     /* per-file compression algorithm */
     /*
      * Force compression on the file using the defrag ioctl, could be
      * different from prop_compress and takes precedence if set
      */
     unsigned defrag_compress;
 
     struct btrfs_delayed_node *delayed_node;
 
     /* File creation time. */
     struct timespec64 i_otime;
 
     /* Hook into fs_info->delayed_iputs */
     struct list_head delayed_iput;
 
     struct rw_semaphore i_mmap_lock;
     struct inode vfs_inode;
 };
 
 static inline u32 btrfs_inode_sectorsize(const struct btrfs_inode *inode)
 {
     return inode->root->fs_info->sectorsize;
 }
 
 static inline struct btrfs_inode *BTRFS_I(const struct inode *inode)
 {
     return container_of(inode, struct btrfs_inode, vfs_inode);
 }
 
 static inline unsigned long btrfs_inode_hash(u64 objectid,
                          const struct btrfs_root *root)
 {
     u64 h = objectid ^ (root->root_key.objectid * GOLDEN_RATIO_PRIME);
 
 #if BITS_PER_LONG == 32
     h = (h >> 32) ^ (h & 0xffffffff);
 #endif
 
     return (unsigned long)h;
 }
 
 static inline void btrfs_insert_inode_hash(struct inode *inode)
 {
     unsigned long h = btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root);
 
     __insert_inode_hash(inode, h);
 }
 
 #if BITS_PER_LONG == 32
 
 /*
  * On 32 bit systems the i_ino of struct inode is 32 bits (unsigned long), so
  * we use the inode's location objectid which is a u64 to avoid truncation.
  */
 static inline u64 btrfs_ino(const struct btrfs_inode *inode)
 {
     u64 ino = inode->location.objectid;
 
     /* type == BTRFS_ROOT_ITEM_KEY: subvol dir */
     if (inode->location.type == BTRFS_ROOT_ITEM_KEY)
         ino = inode->vfs_inode.i_ino;
     return ino;
 }
 
 #else
 
 static inline u64 btrfs_ino(const struct btrfs_inode *inode)
 {
     return inode->vfs_inode.i_ino;
 }
 
 #endif
 
 static inline void btrfs_i_size_write(struct btrfs_inode *inode, u64 size)
 {
     i_size_write(&inode->vfs_inode, size);
     inode->disk_i_size = size;
 }
 
 static inline bool btrfs_is_free_space_inode(struct btrfs_inode *inode)
 {
     struct btrfs_root *root = inode->root;
 
     if (root == root->fs_info->tree_root &&
         btrfs_ino(inode) != BTRFS_BTREE_INODE_OBJECTID)
         return true;
 
     return false;
 }
 
 static inline bool is_data_inode(struct inode *inode)
 {
     return btrfs_ino(BTRFS_I(inode)) != BTRFS_BTREE_INODE_OBJECTID;
 }
 
 static inline void btrfs_mod_outstanding_extents(struct btrfs_inode *inode,
                          int mod)
 {
     lockdep_assert_held(&inode->lock);
     inode->outstanding_extents += mod;
     if (btrfs_is_free_space_inode(inode))
         return;
     trace_btrfs_inode_mod_outstanding_extents(inode->root, btrfs_ino(inode),
                           mod);
 }
 
 /*
  * Called every time after doing a buffered, direct IO or memory mapped write.
  *
  * This is to ensure that if we write to a file that was previously fsynced in
  * the current transaction, then try to fsync it again in the same transaction,
  * we will know that there were changes in the file and that it needs to be
  * logged.
  */
 static inline void btrfs_set_inode_last_sub_trans(struct btrfs_inode *inode)
 {
     spin_lock(&inode->lock);
     inode->last_sub_trans = inode->root->log_transid;
     spin_unlock(&inode->lock);
 }
 
 /*
  * Should be called while holding the inode's VFS lock in exclusive mode or in a
  * context where no one else can access the inode concurrently (during inode
  * creation or when loading an inode from disk).
  */
 static inline void btrfs_set_inode_full_sync(struct btrfs_inode *inode)
 {
     set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
     /*
      * The inode may have been part of a reflink operation in the last
      * transaction that modified it, and then a fsync has reset the
      * last_reflink_trans to avoid subsequent fsyncs in the same
      * transaction to do unnecessary work. So update last_reflink_trans
      * to the last_trans value (we have to be pessimistic and assume a
      * reflink happened).
      *
      * The ->last_trans is protected by the inode's spinlock and we can
      * have a concurrent ordered extent completion update it. Also set
      * last_reflink_trans to ->last_trans only if the former is less than
      * the later, because we can be called in a context where
      * last_reflink_trans was set to the current transaction generation
      * while ->last_trans was not yet updated in the current transaction,
      * and therefore has a lower value.
      */
     spin_lock(&inode->lock);
     if (inode->last_reflink_trans < inode->last_trans)
         inode->last_reflink_trans = inode->last_trans;
     spin_unlock(&inode->lock);
 }
 
 static inline bool btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
 {
     bool ret = false;
 
     spin_lock(&inode->lock);
     if (inode->logged_trans == generation &&
         inode->last_sub_trans <= inode->last_log_commit &&
         inode->last_sub_trans <= inode->root->last_log_commit)
         ret = true;
     spin_unlock(&inode->lock);
     return ret;
 }
 
 /*
  * Check if the inode has flags compatible with compression
  */
 static inline bool btrfs_inode_can_compress(const struct btrfs_inode *inode)
 {
     if (inode->flags & BTRFS_INODE_NODATACOW ||
         inode->flags & BTRFS_INODE_NODATASUM)
         return false;
     return true;
 }
 
 /*
  * btrfs_inode_item stores flags in a u64, btrfs_inode stores them in two
  * separate u32s. These two functions convert between the two representations.
  */
 static inline u64 btrfs_inode_combine_flags(u32 flags, u32 ro_flags)
 {
     return (flags | ((u64)ro_flags << 32));
 }
 
 static inline void btrfs_inode_split_flags(u64 inode_item_flags,
                        u32 *flags, u32 *ro_flags)
 {
     *flags = (u32)inode_item_flags;
     *ro_flags = (u32)(inode_item_flags >> 32);
 }
 
 /* Array of bytes with variable length, hexadecimal format 0x1234 */
 #define CSUM_FMT                "0x%*phN"
 #define CSUM_FMT_VALUE(size, bytes)     size, bytes
 
 static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode,
         u64 logical_start, u8 *csum, u8 *csum_expected, int mirror_num)
 {
     struct btrfs_root *root = inode->root;
     const u32 csum_size = root->fs_info->csum_size;
 
     /* Output minus objectid, which is more meaningful */
     if (root->root_key.objectid >= BTRFS_LAST_FREE_OBJECTID)
         btrfs_warn_rl(root->fs_info,
 "csum failed root %lld ino %lld off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
             root->root_key.objectid, btrfs_ino(inode),
             logical_start,
             CSUM_FMT_VALUE(csum_size, csum),
             CSUM_FMT_VALUE(csum_size, csum_expected),
             mirror_num);
     else
         btrfs_warn_rl(root->fs_info,
 "csum failed root %llu ino %llu off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
             root->root_key.objectid, btrfs_ino(inode),
             logical_start,
             CSUM_FMT_VALUE(csum_size, csum),
             CSUM_FMT_VALUE(csum_size, csum_expected),
             mirror_num);
 }
 
 #endif

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