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authorJan Kara <jack@suse.cz>2013-12-08 21:11:59 -0500
committerTheodore Ts'o <tytso@mit.edu>2013-12-08 21:11:59 -0500
commit30fac0f75da24dd5bb43c9e911d2039a984ac815 (patch)
treee8e31ec8a47149e935ceba868575c1bd6e750633
parent9105bb149bbbc555d2e11ba5166dfe7a24eae09e (diff)
ext4: Do not reserve clusters when fs doesn't support extents
When the filesystem doesn't support extents (like in ext2/3 compatibility modes), there is no need to reserve any clusters. Space estimates for writing are exact, hole punching doesn't need new metadata, and there are no unwritten extents to convert. This fixes a problem when filesystem still having some free space when accessed with a native ext2/3 driver suddently reports ENOSPC when accessed with ext4 driver. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
-rw-r--r--fs/ext4/super.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9d70c0c177c7..1f7784de05b6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3316,11 +3316,19 @@ int ext4_calculate_overhead(struct super_block *sb)
}
-static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
+static ext4_fsblk_t ext4_calculate_resv_clusters(struct super_block *sb)
{
ext4_fsblk_t resv_clusters;
/*
+ * There's no need to reserve anything when we aren't using extents.
+ * The space estimates are exact, there are no unwritten extents,
+ * hole punching doesn't need new metadata... This is needed especially
+ * to keep ext2/3 backward compatibility.
+ */
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
+ return 0;
+ /*
* By default we reserve 2% or 4096 clusters, whichever is smaller.
* This should cover the situations where we can not afford to run
* out of space like for example punch hole, or converting
@@ -3328,7 +3336,8 @@ static ext4_fsblk_t ext4_calculate_resv_clusters(struct ext4_sb_info *sbi)
* allocation would require 1, or 2 blocks, higher numbers are
* very rare.
*/
- resv_clusters = ext4_blocks_count(sbi->s_es) >> sbi->s_cluster_bits;
+ resv_clusters = ext4_blocks_count(EXT4_SB(sb)->s_es) >>
+ EXT4_SB(sb)->s_cluster_bits;
do_div(resv_clusters, 50);
resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);
@@ -4071,10 +4080,10 @@ no_journal:
"available");
}
- err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sbi));
+ err = ext4_reserve_clusters(sbi, ext4_calculate_resv_clusters(sb));
if (err) {
ext4_msg(sb, KERN_ERR, "failed to reserve %llu clusters for "
- "reserved pool", ext4_calculate_resv_clusters(sbi));
+ "reserved pool", ext4_calculate_resv_clusters(sb));
goto failed_mount4a;
}