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[releases.git] / btrfs / btrfs_inode.h

/* 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,
        /* Set when this inode is a free space inode. */
        BTRFS_INODE_FREE_SPACE_INODE,
};

/* 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 rb_root io_failure_tree;
        spinlock_t io_failure_lock;

        /*
         * 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 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;
}

#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)
{
        return test_bit(BTRFS_INODE_FREE_SPACE_INODE, &inode->runtime_flags);
}

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