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hfsplus: prevent btree data loss on ENOSPC

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Inserting or deleting a record in a btree may require splitting several of
its nodes.  If we hit ENOSPC halfway through, the new nodes will be left
orphaned and their records will be lost.  This could mean lost inodes,
extents or xattrs.

Henceforth, check the available disk space before making any changes.
This still leaves the potential problem of corruption on ENOMEM.

The patch can be tested with xfstests generic/027.

Link: http://lkml.kernel.org/r/4596eef22fbda137b4ffa0272d92f0da15364421.1536269129.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ernesto A. Fernández
2018-10-30 15:06:14 -07:00
committed by Linus Torvalds
parent ef75bcc576
commit d92915c35b
5 changed files with 72 additions and 20 deletions
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4
fs/hfsplus/extents.c
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@@ -100,6 +100,10 @@ static int __hfsplus_ext_write_extent(struct inode *inode,
if (hip->extent_state & HFSPLUS_EXT_NEW) {
if (res != -ENOENT)
return res;
/* Fail early and avoid ENOSPC during the btree operation */
res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
if (res)
return res;
hfs_brec_insert(fd, hip->cached_extents,
sizeof(hfsplus_extent_rec));
hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);