xfs: don't return 0 if generic_segment_checks() find nothing to write
PATCH 1/1 xfs: don't return 0 if generic_segment_checks() find nothing to write
From: Jie Liu <[email protected]>
At xfs_file_aio_write(), we just return 0 which means a successfully operation if the ocount is evaluated to 0 at generic_segment_checks(). Generally, it'll occurred if the specified write count is 0 from the user space. However, for example, if the given offset is over the maximum file size limitation although nothing would be written into the file, in this case, the underlying file system should detect this issue and return a proper errno instead. Hence, the beginning pre-checking up against ocount would conceal some real cause and confuse the user space program maybe.
To fix it, we can delay the write count verification until xfs_file_aio_write_checks() is done.
This test is performed on 32-bit system without CONFIG_LBADF is enabled. Before patching:xfs_io -f -c "pwrite 17592186040320 0" /storage/test_file wrote 0/0 bytes at offset 17592186040320
0.000000 bytes, 0 ops; 0.0000 sec (0.000000 bytes/sec and 0.0000 ops/sec)
After patching:xfs_io -f -c "pwrite 17592186040320 0" /storage/test_file
pwrite64: File too large
--- fs/xfs/xfs_file.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
fs/xfs/xfs_file.c +6 -3
@@ -671,6 +671,9 @@ xfs_file_dio_aio_write(if (ret) goto out; +if (ocount ==0 ) + goto out; +if (mapping->nrpages) { ret = -filemap_write_and_wait_range (VFS_I (ip)->i_mapping, pos,-1 );
@@ -725,6 +728,9 @@ xfs_file_buffered_aio_write(if (ret) goto out; +if (ocount ==0 ) + goto out; +/* We can write back this queue in page reclaim */ current->backing_dev_info = mapping->backing_dev_info;
@@ -772,9 +778,6 @@ xfs_file_aio_write(if (ret)return ret; -if (ocount ==0 ) -return 0 ; -sb_start_write (inode->i_sb);if (XFS_FORCED_SHUTDOWN (ip->i_mount)) {
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1.7.9.5 _______________________________________________ xfs mailing list [email protected] http://oss.sgi.com/mailman/listinfo/xfs
Hey Jeff,
Quoted 11 lines · Jeff Liu
From: Jie Liu <[email protected]>
At
xfs_file_aio_write(), we just return 0 which means a successfully operation if the ocount is evaluated to 0 atgeneric_segment_checks(). Generally, it'll occurred if the specified write count is 0 from the user space. However, for example, if the given offset is over the maximum file size limitation although nothing would be written into the file, in this case, the underlying file system should detect this issue and return a proper errno instead. Hence, the beginning pre-checking up against ocount would conceal some real cause and confuse the user space program maybe.To fix it, we can delay the write count verification until
xfs_file_aio_write_checks()is done.
Could you wrap these around 72 columns or so in the future? Don't worry about reposting this one unless something technical comes up.
Thanks,
Ben
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Hi Ben,
Quoted 13 lines · Ben Myers
Hey Jeff,
Quoted 10 lines · Jeff Liu
From: Jie Liu <[email protected]>
At
xfs_file_aio_write(), we just return 0 which means a successfully operation if the ocount is evaluated to 0 atgeneric_segment_checks(). Generally, it'll occurred if the specified write count is 0 from the user space. However, for example, if the given offset is over the maximum file size limitation although nothing would be written into the file, in this case, the underlying file system should detect this issue and return a proper errno instead. Hence, the beginning pre-checking up against ocount would conceal some real cause and confuse the user space program maybe.
Quoted 4 lines
Quoted 1 line
To fix it, we can delay the write count verification until
xfs_file_aio_write_checks()is done.Could you wrap these around 72 columns or so in the future? Don't worry about reposting this one unless something technical comes up.
Sure, I'll take care of the patch format in the future.
Thanks,
-Jeff
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