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authorTheodore Ts'o <tytso@mit.edu>2017-10-06 23:09:55 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-30 08:39:04 +0000
commit9cdd4bfc42685732ac4d77650a4afac4e743b847 (patch)
tree6de3e78c1ad5dc4edcf849b0a87bde9356df36b1 /fs
parent2946ebe90ecf7f506e3e1fc49d41406bfaade551 (diff)
ext4: fix interaction between i_size, fallocate, and delalloc after a crash
commit 51e3ae81ec58e95f10a98ef3dd6d7bce5d8e35a2 upstream. If there are pending writes subject to delayed allocation, then i_size will show size after the writes have completed, while i_disksize contains the value of i_size on the disk (since the writes have not been persisted to disk). If fallocate(2) is called with the FALLOC_FL_KEEP_SIZE flag, either with or without the FALLOC_FL_ZERO_RANGE flag set, and the new size after the fallocate(2) is between i_size and i_disksize, then after a crash, if a journal commit has resulted in the changes made by the fallocate() call to be persisted after a crash, but the delayed allocation write has not resolved itself, i_size would not be updated, and this would cause the following e2fsck complaint: Inode 12, end of extent exceeds allowed value (logical block 33, physical block 33441, len 7) This can only take place on a sparse file, where the fallocate(2) call is allocating blocks in a range which is before a pending delayed allocation write which is extending i_size. Since this situation is quite rare, and the window in which the crash must take place is typically < 30 seconds, in practice this condition will rarely happen. Nevertheless, it can be triggered in testing, and in particular by xfstests generic/456. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reported-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/extents.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a3e0b3b7441d..a77cbc5b657b 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4803,7 +4803,8 @@ static long ext4_zero_range(struct file *file, loff_t offset,
}
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
- offset + len > i_size_read(inode)) {
+ (offset + len > i_size_read(inode) ||
+ offset + len > EXT4_I(inode)->i_disksize)) {
new_size = offset + len;
ret = inode_newsize_ok(inode, new_size);
if (ret)
@@ -4974,7 +4975,8 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
}
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
- offset + len > i_size_read(inode)) {
+ (offset + len > i_size_read(inode) ||
+ offset + len > EXT4_I(inode)->i_disksize)) {
new_size = offset + len;
ret = inode_newsize_ok(inode, new_size);
if (ret)