4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o <tytso@xxxxxxx> [ Upstream commit 73c384c0cdaa8ea9ca9ef2d0cff6a25930f1648e ] We can't fail in the truncate path without requiring an fsck. Add work around for this by using a combination of retry loops and the __GFP_NOFAIL flag. From: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Anna Pendleton <pendleton@xxxxxxxxxx> Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx> Link: https://lore.kernel.org/r/20200507175028.15061-1-pendleton@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Stable-dep-of: c26ab35702f8 ("ext4: fix slab-use-after-free in ext4_split_extent_at()") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ext4/ext4.h | 1 + fs/ext4/extents.c | 43 +++++++++++++++++++++++++++++++++---------- 2 files changed, 34 insertions(+), 10 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index fa2579abea7df..3871df6b67322 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -629,6 +629,7 @@ enum { */ #define EXT4_EX_NOCACHE 0x40000000 #define EXT4_EX_FORCE_CACHE 0x20000000 +#define EXT4_EX_NOFAIL 0x10000000 /* * Flags used by ext4_free_blocks diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 1762a6330a53c..080a7a401a4e1 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -290,11 +290,14 @@ ext4_force_split_extent_at(handle_t *handle, struct inode *inode, { struct ext4_ext_path *path = *ppath; int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext); + int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO; + + if (nofail) + flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL; return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ? EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0, - EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO | - (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0)); + flags); } /* @@ -536,8 +539,12 @@ __read_extent_tree_block(const char *function, unsigned int line, { struct buffer_head *bh; int err; + gfp_t gfp_flags = __GFP_MOVABLE | GFP_NOFS; + + if (flags & EXT4_EX_NOFAIL) + gfp_flags |= __GFP_NOFAIL; - bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS); + bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags); if (unlikely(!bh)) return ERR_PTR(-ENOMEM); @@ -879,6 +886,10 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, struct ext4_ext_path *path = orig_path ? *orig_path : NULL; short int depth, i, ppos = 0; int ret; + gfp_t gfp_flags = GFP_NOFS; + + if (flags & EXT4_EX_NOFAIL) + gfp_flags |= __GFP_NOFAIL; eh = ext_inode_hdr(inode); depth = ext_depth(inode); @@ -899,7 +910,7 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, if (!path) { /* account possible depth increase */ path = kcalloc(depth + 2, sizeof(struct ext4_ext_path), - GFP_NOFS); + gfp_flags); if (unlikely(!path)) return ERR_PTR(-ENOMEM); path[0].p_maxdepth = depth + 1; @@ -1049,9 +1060,13 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode, ext4_fsblk_t newblock, oldblock; __le32 border; ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ + gfp_t gfp_flags = GFP_NOFS; int err = 0; size_t ext_size = 0; + if (flags & EXT4_EX_NOFAIL) + gfp_flags |= __GFP_NOFAIL; + /* make decision: where to split? */ /* FIXME: now decision is simplest: at current extent */ @@ -1085,7 +1100,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode, * We need this to handle errors and free blocks * upon them. */ - ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), GFP_NOFS); + ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags); if (!ablocks) return -ENOMEM; @@ -2075,7 +2090,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, if (next != EXT_MAX_BLOCKS) { ext_debug("next leaf block - %u\n", next); BUG_ON(npath != NULL); - npath = ext4_find_extent(inode, next, NULL, 0); + npath = ext4_find_extent(inode, next, NULL, gb_flags); if (IS_ERR(npath)) return PTR_ERR(npath); BUG_ON(npath->p_depth != path->p_depth); @@ -2878,7 +2893,8 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, ext4_fsblk_t pblk; /* find extent for or closest extent to this block */ - path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE); + path = ext4_find_extent(inode, end, NULL, + EXT4_EX_NOCACHE | EXT4_EX_NOFAIL); if (IS_ERR(path)) { ext4_journal_stop(handle); return PTR_ERR(path); @@ -2960,7 +2976,7 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, le16_to_cpu(path[k].p_hdr->eh_entries)+1; } else { path = kcalloc(depth + 1, sizeof(struct ext4_ext_path), - GFP_NOFS); + GFP_NOFS | __GFP_NOFAIL); if (path == NULL) { ext4_journal_stop(handle); return -ENOMEM; @@ -3382,7 +3398,7 @@ static int ext4_split_extent(handle_t *handle, * Update path is required because previous ext4_split_extent_at() may * result in split of original leaf or extent zeroout. */ - path = ext4_find_extent(inode, map->m_lblk, ppath, 0); + path = ext4_find_extent(inode, map->m_lblk, ppath, flags); if (IS_ERR(path)) return PTR_ERR(path); depth = ext_depth(inode); @@ -4677,7 +4693,14 @@ int ext4_ext_truncate(handle_t *handle, struct inode *inode) } if (err) return err; - return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1); +retry_remove_space: + err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1); + if (err == -ENOMEM) { + cond_resched(); + congestion_wait(BLK_RW_ASYNC, HZ/50); + goto retry_remove_space; + } + return err; } static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset, -- 2.43.0
